Altadena orginially was the northernmost portion of Ranch San Pascqual, established by the Mexican government in 1826 after it claimed independence from Spain.

In 1880, Frederick and John Woodbury of Marshalltown, Iowa, purchased 937 acres that later came to be known as the Woodbury Ranch. They submitted a plot plan for a residential dvelopment in 1887 known as the Woodbury Subdivision. They decided to call the new community Altadena after a local nursery, with "alta" from the Spanish word meaning "high" and "dena" from Pasadena.

Streets running east and west were named after California counties and avenues running north and south after Spanish female saints. Many of those names still exist: Mariposa, Mendocino, Santa Clara, Santa Margarita, Calaveras and Santa Barbara. Lake Avenue was named for a lake that existed in Pasadena. Over the years, Altadena has been subject to annexation by Pasadena. Annexation was stopped in 1956 by the collective will of the community, thought it has been attempted several times since then without success. -Emanuel Parker-